The purpose of this study was to investigate how two female students participated in science practices as they worked in a multimedia case‐based environment: interpreting simulated results, reading and writing multiple texts, role‐playing, and Internet conferencing. Using discourse analysis, the following data were analyzed: students' published web posters, Internet conferencing logs between American and Zimbabwean university students, and a focus group interview. Three constructs supported the development of these students' identities in practice: (a) multimedia cases creating emotional involvement; (b) authoring web posters, and role‐playing situated in cross‐cultural social networks; and (c) altruism associated with relevant global topics. The investigators argue that educators and developers of online learning environments consider social contexts, authoring, and opportunities for cross‐cultural interaction to support participation in science practices. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1116–1136, 2010